The IS31LT3354 is a continuous mode inductive
step-down converter, designed for driving a single LED
or multiple series connected LEDs efficiently from a
voltage source higher than the required LED voltage.
The device operates from an input supply between 6V
and 40V and provides an externally adjustable output
current of up to 2A or even higher, which is determined
by the external MOSFET and inductor.
The IS31LT3354 includes a high-side output current
sensing circuit, which uses an external resistor to set
the nominal average output current.
Output current can be adjusted linearly by applying an
external control signal to the ADJ pin. The ADJ pin will
accept either a DC voltage or a PWM waveform. This
will provide either a continuous or a gated output
Applying a voltage of 0.2V or lower to the ADJ pin
turns the output off and switches the chip into a low
current standby state.
The chip is assembled in SOT23-5 package.